With development of the touch screen technology, more and more electronic device is provided with a touch screen nowadays. When a finger of a user is touching the touch screen, a noise signal may be received by the touch screen, besides an operation signal from the finger of the user being received. A SNR parameter represents a ratio of the operation signal to the noise signal in the touch screen. Thus, the SNR parameter is one of important indices for evaluating performance of the touch screen. The higher a value of the SNR parameter is, the higher an accuracy of identifying a touch action on the touch screen to which the SNR parameter is applied is. In conventional solutions, a drive integrated circuit (hereinafter referred to as a drive IC) of the touch screen calculates based on a obtained capacitance signal of the touch screen by a standard deviation algorithm, a root-mean-square algorithm (RMS) algorithm or a peak-to-peak algorithm to obtain the SNR parameter.
However, inventors found during a test process that the value of the SNR parameter calculated by the algorithm, such as the standard deviation algorithm, the RMS algorithm or the peak-to-peak algorithm, is lower, and thus the accuracy of identifying the touch action on the touch screen is lower.